You read something and read it again, go back and reread it, you have some trouble understanding it, or maybe you have some thoughts you want to pursue.
A smart reader (browser extension, e-book function, etc.) that suggests more information based on your behavior while reading. For instance, if you read at a certain pace, and you stay longer on a paragraph, you might get a pop up asking if you need to dig deeper into details or would like to expand by getting related information.
Test yourself. Are you a lateral thinker?
Have an app and a site where on one side people contribute puzzles and on the other side people try and solve them. Puzzle contributions are screened and published by editors who decide if they feet the lateral thinking criteria.